Multiple-switch starter.



T. E. BARNUM.

MULTIPLE SWITCH STARTER.

. APPLIOATION FILED mu zo, 1901. nmwnwnn L11, 1909.

ZSHEBTS-SHEET 1.

INVNTOR Patented Apr. 20, 1909.

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ATTORNEY T. E. BARNUM. MULTIPLE SWITCH STARTER, APPLICATION rum) KAY 20, 1907'. nnnwnn up. 11, 1909.

Patented Apr. 20, 1909.

2 BHEETS-SHEET 2.

WITNESSES:

I ATTORNEY- TH lnollm: rrrnu cm, wunmmu, n c.

UNITED STATES PATENT OFFICE.

THOMAS BARNUM, or MILWAUKEE, WISCONSIN, ASSIGNQR TO THE CUTLER-HAMMER MFG. co, or MILWAUKEE, WISCONSIN, A oonror 'rio v or WISCONSIN.

MULTIPLE-SWITCH STARTER;

Specification of Letters Patent.

Patented April 20, 1909.

Application filed May 20, 1907, Serial No. 374,628. Renewed January 11, 1909. Serial No. 471,752.

To all whom it may concern:

Be it known that I, THOMAS E. BARNUM, a citizen of the United States, residing at Milwaukee, in the county of Milwaukee and State of lVisconsin, have invented new and useful Improvements in Multiple- Switch Starters, of which the following is a full, clear, concise, and exact description, reference being bad to the accompanying drawing, forming a part of this specification.

My invention relates to improvements in motor controllers.

It is particularly applicable to motor controllers in which a plurality of hand-open ated switches are adapted to be operated for controlling the motor resistance.

One of the objects of my invention is to prevent the leaving of the starting resistance in circuit longer than a predetermined period.

The starting resistance of the motor is usually constructed of wire which, while it is adapted to carry the current for a short period of time, is not adapted to carry the current for any great length of time. It is, therefore, desirable to provide some means to prevent careless or ignorant operators from leaving the resistance in circuit for longer than a predetermined period. To this end, in the present invention, I provide a retaining device, preferably in the form of a low voltage device, for holding closed a switch among a plurality of switches for controlling the starting resistance for controlling the motor circuit, and a device operatively connected with said low voltage device, directly affected by heat to cause said low voltage device to cause the circuit to be opened when the resistance is left in circuit for longer than a predetermined period. I also provide means which, when all the resistance is removed from circuit, is operated to render said device ineffective.

For the purpose of disclosing my invention, I have illustrated in the accompanying drawings certain forms which my invention may take.

In said drawings Figure 1 is a front elevation of the starting device embodying my invention, Fig. 2 is a side elevation thereof, Fig. 3 is a cross-sectional view of oneof the operating handles and a top plan viewof the rocking dogs, Fig. t-is a detail elevation'of the latching mechanism forthe operating handles, Fig. 5 is a detail perspective of one of the rocking dogs, Fig. 6 is a dia rammatic view of the circuit arrangement of the device illustrated in Fig. 1, Fig. 7 is a detail view of the means for rendering the switch opening means ineffective, Fig. 8 is a diagrammatic view of another form my invention may take, and Fig. 9 is a detail view of the means for ren dering the switch opening means shown in Fig. 8 ineifective.

In the structure illustrated in Figs. 1 to 5, the several switch levers or arms 1, 1, 1 and 1 are suitably pivoted or journaled at one end, and are provided at the opposite end with suitable operating handles. 1 have shown the several switch levers as journaled upon a suitable rod or shaft 2 mounted in bearings 3 upon the brackets The brackets l also support a rod 5 which is threaded through a rubber tube 6 adapted to serve as a cushion or buffer against which the extended ends of the switch arms or levers impinge when the switch arms are thrown open. Each of the levers carries a contact device '7 which is preferably formed of a number of strips of copper laid face to face, the free ends being adapted to engage contact surfaces. Upon the base board 8, upon which the various parts of the switch are carried, is mounted a contact pole 9 with which one end of the contact device 7 of each arm or lever is adapted to engage, the other end of said device being adapted to engage one of the contact terminals 10, 10, 10 and 10.

Upon the terminal 10 is provided a binding post 11, by which electrical connection made therewith, and the second binding post 12 is carried upon the terminal 10 for a like purpose. Upon the terminal 10 is also mounted a carbon block 13 and a similar carbon block 1a is mounted upon the end of the contact bar 9. The first switch arm 1 carries laterally extending arms 15 and 16 adapted to support on the ends thereof carbon blocks 17 and 18 which, when the switch arm 1 is moved to close the circuit, engage respectively the contact blocks 13 and 14, thereby closing the circuit from the terminal 10 to the terminal 9. The further movement of the switch arm 1 causes the contact device 7 thereof to directly close together the terminals '10 and 9. Likewise, when the switch arm'l is-moved outward, the contact device 7 leavesthe terminals 10 and .9 before the carbon blocks separate so that any are whichl magnet to release the switches and permit may be formed by the opening of the circuit the same to open unless all of the switches will take place between the carbon blocks instead of between the metal surfaces.

Near the upper end of the switch arm 1, a lug 19 is provided which carries a laterally extending catch 20 which may take the form of a screw. Mounted upon the base board 8 above the arm 1 is a retaining magnet 21, having an armature 22 pivoted at 23. The armature carries an upwardly extending lug 24-, and when the arm 1 is moved to close the circuit, the catch 20 engages the side of the armature 22 and moves the same against the magnet pole and the magnetism of the mag net 21 retains the armature 22 in this position. The swinging of the armature 22 carries the lug 2% upon the exterior of the catch 20 so that said catch will rest in the slot formed between the lug 2d and the face of the armature 22. So long as the magnet 21 remains energized, the arm 1 will thus be held in the closed position. When, however, the magnet 21 is deenergized, the armature 22 will be released and the weight of the arm 1 will carry the same into the position shown in Fig. 2, thereby rocking the armature 22 upon its pivot, as shown.

Mounted upon a rod or shaft 25, supported in suitable bearings upon the base plate 8, are rocking dogs 26, 26 and 26*. Each of the dogs has its rear so shaped as to engage the base plate 8 and limit the downward movement of the dog when free. Upon the end of the dog to the right hand side,

'an upwardly extending lip 27 is provided,

which has its front edge curved and its rear edge perpendicular to the upper surface of the dog. The under side of the dog has a lip 28 extending throughout its whole length, which lip is rounded at the left hand edge.

The levers 1 to 1, inclusive, are each provided with a catch 29 pivoted to the arm or lever at 30, and set in the slot 31, the walls of which slot limit the vertical movement of the latch relatively to the arm. Below the latch and formed integral with the lever is a lug 32 projecting toward the base plate 8 and consisting of two parts 33 and 3a. The part 33 is square in section and flat upon the end and when the lever is in the position to close the circuit presents a vertical surface. The upper part of the part 34: is inclined or chamfered at an acute angle.

The last lever 1 carries a laterally extending arm 35, preferably formed of insulating material to which is attached a spring contact 36, preferably in the form of spring contacts. These contacts are adapted when the last switch 1 is closed to engage stationary contacts 37 and 38 secured to the face of the base plate 8.

For controlling the circuit through the retaining magnet 21 during the closing operation of the switches, and for causing said are closed within a predetermined time, I have provided a switch 39. This switch is preferably formed of two materials having different coefficients of expansion when subjected to heat, and which, when closed, is adapted to engage the stationary contact 40, mounted upon the face of the plate or base 8. The materials from which the switch is formed are preferably formed in strips laid face to face, and as the coeflicient of one is greater than that of the other when subjected to heat, when the switch is affected by heat, the difference in expansion of the two materials will cause the switch to open.

In Fig. 6 1 have illustrated, diagrammatically, the circuit arrangement of the device illustrated in Figs. 1 to 5. In said figure the contact terminal 10 is connected with the positive side 41 of the line. Contact terminal 1O is connected by the conductor 12 with one terminal of the armature 43 of the motor, the opposite terminal of said armature being connected by conductor 1 1 with the negative side 45 of the line. The contact strip or bar 9 is connected by conductor 16 with one terminal of the field winding 17 of the motor, the opposite terminal of which is connected with the conductor 1%. One terminal of the winding of the magnet 21 is connected by the conductor as with the contact bar or strip 9 and the opposite terminal of said windin is connected by a conductor 49 with the stationary contact 40 of the switch 39. The switch 39 is connected through the high resistance 50 with the negative side 15 of the line, and by conductor 51 with the stationary contact 37. The contact 40 of the switch 39 is connected by conductor 52 with the stationary contact 38 of the switch 36. Connected between the terminal 10 and the contact bar 9 is a section 53 of resistance. A resistance 54 is also connected between the contact 10 and the contact terminal 10, and is divided in sections and connected with the contact terminal 10 The operation of the device as above described is as follows: Assuming that it be desired to start the motor, the switch arm 1 is closed to first close the circuit between the carbon blocks and finally to close together the terminals 10 and 9 directly through the contact device 7 of the switch arm 1. The armature 22 is engaged by the catch 20 and moved against the pole of the retaining magnet 21. As soon as the switch arm 1 is closed, circuit is established from the positive side 41 to the contact 10, and thence across the switch arm 1, to the contact 9, by conductor 48, through the winding 21, by conductor 49 across the switch 39, and through the high resistance 50 to the negative side 45 of the line. The magnet 21 is thus energized and retains the switch arm 1 in its closed position. The closing of the switch arm 1 also closes the circuit from the positive side 41 to the contact 10 and thence across the arm 1 to the contact 9, through the resistance 53 and 542 to contact 10 thence by conductor 42 through the armature 4:3 and by conductor 4-4 to the negative side 45 of the line. At the same time the field circuit is established fromthe contact bar 9 by conductor 16, through field winding 47 and thence by conductor 4 1 to the negative side 45 of the line. In moving the arm 1 to the closed position, the oblique wall 3% of the lug 32 on the arm 1 engages the under face of the first rocking dog 26 and moves the same into the position shown in full lines in Fig. i. The second switch arm 1 is now closed and as the dog 26 is in its raised position, the latch 29 of the arm 1 will ride ver the lip 27 of the dog 26 and engage the vertical wall thereof and the switch arm 1 will thus be held in closed position. The closing of the switch arm 1 cuts out the resistance 53 from the motor circuit and increases the speed of the motor. The closing of the switch arm 1 causes the inclined face 34: of the dog 32 thereof to engage under the rocking do 2 raising the same to the position where it will be engaged by the catch 29 of the arm 1". In a like manner the remaining switches are closed and held, and all the starting resistance is removed from circuit. It will be noted that the switch 39, as long as the last switch arm 1 remains open, is in series with the winding of the magnet 21. If, during the operation of closing, the operator fails to close the last switch within a predetermined time, the current passing through the switch 39 will heat the same and due to the difference in the coeflicients of expansion of the metals composing this switch, the switch will twist, and moving off of its contact l0 open the circuit of the magnet 21, thereby permitting all of the switches closed to open. When the last switch is closed, the arms of the switch 36 carried thereby are moved into engagement with the contacts 37 and 38, thereby bridging the contacts and closing a short-circuit around the switch 39 to render the same ineifective. If it be desired to cut in the resistance and open the motor circuit, the retaining magnet 21 may be deenergized in any suitable manner and the arm 1 will. be released and fly outward to the position shown in Fig. 2. In moving utwa-rd, the first rocking dog 26 is permitted to fall and the latch of the second switch arm 1 is thus released, and as said switch arm likewise flies upward, it permits the rocking dog 26 to fall, thereby releasing the third switch arm, and in a similar manner the fourth switch arm is permitted to open. Any attempt to close one of the switches out of its regular order will be prevented due to the fact that the Hat face 3 will engage the end of the rocking dog when the dog is in its lowered position, and it is only when the dog has been raised to its upper position that the flat face 34: is permitted to pass beneath the end of the rocking dog. liloreover, unless the rocking dog is in its upper position the latch 29 will not engage the lip 27 upon the dog, and the rocking dog will be held in the upper position only when the immediately preceding switch arm has been closed.

In Figs. 8 and 9 I have shown a modification of the device heretofore described. In the device heretofore described, the switch 39 has been operated by current passing through the same. In the device illustrated in Figs. 8 and 9 the current instead of passing through the switch 39, passes through the high resistance 50 in proximity to which is arranged the switch 39, whereby the heat developed in the resistance 50 will aifect the switch 39 to close the same, and thereby close a short-circuit around the magnet 21. More fully describing this structure, the motor connections are the same as the motor connections described with respect to Fig. 6. One terminal of the magnet 21, instead of being connected through the switch 39, and the high resistance 50, with the negative side 45 of the line, is connected directly through the high resistance with the negative side of the line. This terminal, however, is also connected with the switch 39. The opposite terminal of the magnet is connected, as illustrated with respect to Fig. 6, with the contact 9. This terminal is also connected by the conductor 55 with the S133. tionary contact 56 of the switch 5?. The opposite contact 58 of this switch is connected by conductor 59 with the stationary contact 4:0 of the switch 39. Instead of arranging the switch 57 to be closed upon the closing of the last switch contact 1, as is the fact with respect to the switch 35, the switch 5 is adapted to remain closed as long as the switch arm 1 remains open. The circuit through the magnet, therefore, as long as the switch (rm remains open, extends from the positive side 41 of the line, across the first switch arm 1 to the contact bar 9 and thence by conductor 48 through the retaining magnet 21, through the high resistance 50 to the negative side of the line. If, during the starting operation, the switches are not all closed within a. predetermined time, or if the operator, due to carelessness or neglect, fails to close all of the switches before leaving the same, the heat developed by current passing through the high resistance 50 will affect the switch 39 to cause the same to engage its contact 40, thereby closing a short-circuit from the conductor 48 by conductor 55, to contact 56, across the switch 57 to contact 58, and thence switch for rendering said means ineiiective.

by conductor 4-9 across the switch 39, through the high resistance 50 to the negative side l5 of the line. The short-circuiting of the magnet 21 deenergizes the'same and permits the switches which have been closed to fly open. When the last switch 1 is closed, however, the switch 57 is opened, thereby opening the short-circuit which may be closed by the switch 39, and rendering said switch 39 inefiective and the retaining magnet will hold the switches in their closed position.

While I have describedthe switches as being adapted to be closed in a certain sequence, it will be understood that they may be closed in any other manner, or in any other sequence. Furthermore, while my device is particularly applicable to starting electric motors, it will be understood that the same may be applied to any other use where it is desirable to provide a plurality of hand-operated switches which must be closed within a predetermined period.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is 1. In a controller for electric motors, the combination with a resistance, of a switch tending to stand in open position and adapted to be operated to close the motor circuit, a retaining magnet for holding said switch closed, means directly affected by heatfor causing said retaining m agnet to release said switch, unless said resistance is removed from circuit within a predetermined time, and a switch adapted to be operated upon the removal of all of said resistance from circuit for rendering said means ineffective.

2. The combination with a plurality of switches, of retaining means for holding the same closed, means adapted to be directly affected by heat for causing the said retaining means to permit said switches to open when part of the same remain open for longer than a predetermined period, and means operated upon the closing of the last 3. The combination with a plurality of switches, of a retaining means for holding. the same closed, means adapted to be directly affected by heat for causing said retaining means to permit said switches to open when part of the same remain open longer than a predetermined period and a switch operated upon the closure of the last switch for rendering said means inefiective.

a. The combination with a resistance, of a plurality of switches for controlling the same, one of said switches being adapted to control the motor circuit, a low voltage device for retaining said switch closed, a switch adapted to be directly affected by heat for causing said low voltage device to cause the motor circuit to be opened in the event said resistance is left in circuit for longer than a predetermined time, and means operated upon the closing of the last switch for rendering said low voltage device switch ineffective.

5. The combination with a resistance, of a plurality of switches for controlling the same, one of said switches being adapted to control the motor circuit, a low voltage device for holding said switches closed, a-switch adapted to be directly aiiected by heat for controlling the low voltage device, and adapted to cause said low voltage device to cause the circuit to be opened in event the resistance is left in circuit for longer than a predetermined period and means operated by the closing of the last switch for rendering said low voltage device controlling switch ineffective.

6. The combination with a resistance, of a plurality of switches, one of said switches being adapted to control the motor circuit, a low voltage device for retaining the-same closed, a switch composed of materials whose coefiicient of expansion varies under the influence of heat, for causing said low voltage device to cause the motor circuit to be opened in event the resistance is left in circuit for longer than a predetermined period, and means operated upon the closing of the last switch for rendering said low voltage switch inefiecti've.

7. In a controller for electric motors, the combination with a plurality of switches tending to stand in open position, a plurality 01" sections or" resistance controlled thereby, means insuring the closure or" said switches in a definite sequence, a retaining magnet for holding the first switch of the sequence closed, means operated upon the closure of each switch for holding a succeeding switch closed, a switch adapted to be directly affected by heat for causing said retaining magnet to release said switches, unless the same are closed within a predetermined time and a switch adapted to be actuated upon the closure of the last switch of the sequence for rendering said second mentioned switch ineffective.

In witness whereof, I have hereunto subscribed my name in the presence of two witnesses. Y

THOMAS E. BARNUM. Vitnesses:

OSCAR A. KELLER, CHESTER ALLEN. 

